The invention relates to a structure for connecting a piston to a crankshaft via a connecting rod in a reciprocating engine so as to convert a reciprocating motion of the piston into a rotational motion of the crankshaft.
For cost reduction and reliability assurance, a forged connecting rod is generally used to connect a piston to a crankshaft in an internal combustion engine. In recent years, several active efforts have been made to achieve the weight reduction of various engine moving parts in order to increase engine power and fuel efficiency. It is thus desired to provide a connecting rod with a reduced weight and high strength. In view of the foregoing, Japanese Laid-Open Patent Publication No. 5-070879 proposes a connecting rod made of an aluminum alloy material for use in a relatively low-load engine.